Assuming you are speaking of the tc-8.x x86 version of libreoffice, I saw the same thing when trying to save in odt format initially.

Next I tried to save a file in docx format, which worked without errors. After that I noticed that, despite the error message, the file had been saved in odt format anyway - I was then able to open, modify and save this file and any others I tried in odt format.